Wild Yam.Dioscorea villosa and Phytochemicals.

Contents

• Botanical Basic data of Wild Yam.Dioscorea Villosa.
• Botanical Description of Wild Yam.Dioscorea Villosa.
• Properties of Wild Yam.Dioscorea Villosa.
• Wild Yam and Its Phytochemicals.
• Discover of disgenin from Wild Yam.Dioscorea Villosa.
• Food and Pharmaceutical Uses of Wild Yam:Huai Shan Yao.
• What is hormone banlancing mechanism? Wild Yam act as hormone balancer,diosgenin as substitution of progesterone.
• Breast Enlargement effect of Diosgenin as phytoestrogens.
• Why should Women Use Wild Yam?
• Therapeutic Action,Pharmacology and application of Wild Yam.Dioscorea Villosa and diosgenin.
• Dosage Recomments,Safety Toxicity and Administrations.
• Conclusions and summary.
• Final report of the amended safety assessment of Dioscorea Villosa Wild Yam root extract.
• Uses based on scientific evidence.
• Diosgenin and Wild Yam Research Update.
• Dioscorea Use in Chinese Medicine.
• How Search engine think about Diosgenin and Yam.
• Research update.
• Photo Gallery of Dioscorea villosa.

Diosgenin and Wild Yam Research Update.:

Diosgenin, a plant steroid, induces apoptosis in human rheumatoid arthritis synoviocytes with cyclooxygenase-2 overexpression:

 Rheumatoid arthritis (RA) is an inflammatory joint disease in which perpetuation of chronic synovitis leads to bone and cartilage degradation. Inflammatory cytokines or soluble factors are essential in the pathogenesis of RA. IL-1 and tumor necrosis factor-alpha are the principal mediators of tissue destruction in many immunoinflammatory diseases such as RA. The two cytokines induce, in synergy, the production of high levels of matrix metalloproteinases by synovial cells and chondrocytes. IL-6 and IL-8 also participate in the pathogenesis of RA; for example, IL-6 supports the proliferation of synovial cells, while IL-8 promotes the formation of new blood vessels in synovial membrane.

 RA is characterized by the proliferation of synoviocytes, which also produce prostanoids. Eicosanoids and prostanoids are important lipid mediators that are produced at elevated levels in inflamed tissues including rheumatoid synovium and in cultured human RA fibroblast-like synoviocytes (FLS). Cyclooxygenase (COX), which converts arachidonic acid into prostaglandin endoperoxides, is the rate-limiting enzyme in prostanoid synthesis. At least two forms of COX have been identified and their genes have been cloned. COX-1 is constitutively expressed in most cells and tissues. In contrast, COX-2 is highly inducible by serum, growth factors, lipopolysaccharides, and cytokines, especially interleukin-1 (IL-1), in certain cell types involved in inflammatory processes, e.g. fibroblasts and macrophages. Crofford and co-workers showed that IL-1beta enhanced de novo synthesis of COX-2 - but not of COX-1 -mRNA and protein either in rheumatoid synovial explants or in cultured rheumatoid synoviocytes. These observations suggest that COX-2 may play an important part in the overproduction of prostaglandin E₂ (PGE₂) by rheumatoid synovia.


 Recent reports have outlined the role of COX-2 and prostaglandins in cell apoptosis, particularly in cancer cells. Overexpression of the COX-2 gene protects cancer cells from apoptosis, and drugs that inhibit COX-2 have been shown to induce programmed death in these cells. In addition, the use of nonsteroidal anti-inflammatory drugs (specific or nonspecific COX-2 inhibitors) has been shown to reduce the size and number of neoplastic polyps in patients with familial polyposis. Alterations in the apoptosis of synovial cells have been described in resident synoviocytes as well as in inflammatory cells and are associated with the pathogenesis of RA. These changes constitute hallmarks of synovial cell activation and contribute to both chronic inflammation and hyperplasia. RA FLS are affected most prominently, and their resistance to apoptosis has been linked closely to the progressive destruction of articular cartilage. The role of COX-2 and prostaglandins in synoviocyte death is still under investigation.

 We have investigated for the first time the effect of diosgenin, a plant steroid, on the proliferation rate and apoptosis in the human RA FLS. Particular attention was paid to the modulation of COX-2 expression and activity in RA synoviocyte viability.

 In the present study, we have shown for the first time that a plant steroid, diosgenin, causes an inhibition of the growth of fibroblast-like synoviocytes from human rheumatoid arthritis, with apoptosis induction associated with cyclooxygenase-2 (COX-2) up-regulation. Celecoxib, a selective COX-2 inhibitor, provoked a large decrease in diosgenin-induced apoptosis even in the presence of exogenous prostaglandin E2, whereas interleukin-1beta, a COX-2 inducer, strongly increased diosgenin-induced apoptosis of these synoviocytes. These findings suggest that the proapoptotic effect of diosgenin is associated with overexpression of COX-2 correlated with overproduction of endogenous prostaglandin E2. We also observed a loss of mitochondrial membrane potential, caspase-3 activation, and DNA fragmentation after diosgenin treatment.


 The effects of sustained delivery of diosgenin on the adrenal gland of female rats:

 Diosgenin is a steroidal saponin, which is extracted from the root of Wild Yam (Dioscorea villosa). It has been reported to have tremendous medical applications. In addition, as an herbal extract it appears to be free of any major adverse effects. Recently, Wild Yam has been used to minimize post-menopausal symptoms and is sold unregulated over the counter at a variety of pharmacy and health food stores. The specific objectives of this study were to continuously deliver diosgenin to adult ovariectomized female rats for 45 days and follow changes in body weight, organ weight and histopathological changes in the adrenal gland. Adult female Sprague Dawley rats were divided into three equal groups (n = 54, 250-300 gm BW). Rats in group I served as the control group, animals in group II were ovariectomized and animals in group II were ovariectomized, and supplemented with tricalcium phosphate (TCP) drug delivery system loaded with 500 mg diosgenin.

 The results indicated that ovariectomized animals had a significant increase in body weight and spleen weights. Slight increases in wet adrenal weights were observed in the ovariectomized group compared to the control animals. Histopathological evaluation of the adrenal gland revealed an increase in the cortical and medullary adrenal areas of the ovariectomized group and a significant decrease in these areas in the diosgenin treated animals (p less than 0.001). The information is considered important because reduction in adrenal mass may poses a potential for major endocrine complications.


 Effects of wild yam extract on menopausal symptoms, lipids and sex hormones in healthy menopausal women.:

 Many women seek alternatives to hormonal therapies for the management of menopausal symptoms. Among the treatments currently popular are extracts of wild yam (Dioscorea villosa), which are applied topically in the form of a cream. These preparations are known to contain steroidal saponins, including diosgenin, which has been claimed to influence endogenous steroidogenesis. However, there have been no studies of the safety or efficacy of these preparations in the management of menopausal symptoms.

 Methods: We therefore conducted a double-blind, placebo-controlled, cross-over study of the effects of a wild yam cream in 23 healthy women suffering from troublesome symptoms of the menopause. After a 4-week baseline period, each woman was given active cream and matching placebo for 3 months in random order. Diaries were completed over the baseline period and for 1 week each month thereafter, and blood and saliva samples were collected at baseline and at 3 and 6 months, for measurement of lipids and hormones.

 Results: The average age of the subjects was 53.3 +/- 1.1 (SEM) years and average time since last period 4.3 +/- 0.9 years. At baseline, the average body mass index was 27.3 +/- 0.8, cholesterol level 5.7 +/- 0.2 mmol/l and follicle stimulating hormone (FSH) level 74.2 +/- 5.1 IU/l; estradiol levels were undetectable in the majority of cases. After 3 months of treatment, no significant side-effects were reported with either active treatment or placebo, and there were no changes in weight, systolic or diastolic blood pressure, or levels of total serum cholesterol, triglyceride, high-density lipoprotein (HDL) cholesterol, FSH, glucose, estradiol, or serum or salivary progesterone. Symptom scores showed a minor effect of both placebo and active treatment on diurnal flushing number and severity and total non-flushing symptom scores, and on nocturnal sweating after placebo, but no statistical difference between placebo and active creams.

 Conclusions: This study suggests that short-term treatment with topical wild yam extract in women suffering from menopausal symptoms is free of side-effects, but appears to have little effect on menopausal symptoms. It emphasizes the importance of careful study of treatments for menopausal symptoms if women are to be adequately informed about the choices available to them.


 Estrogen and progestin bioactivity of foods, herbs, and spices.:

 In this study we report on the content and bioactivity of plant (phyto) estrogens and progestins in various foods, herbs, and spices, before and after human consumption. Over 150 herbs traditionally used by herbalists for treating a variety of health problems were extracted and tested for their relative capacity to compete with estradiol and progesterone binding to intracellular receptors for progesterone (PR) and estradiol (ER) in intact human breast cancer cells. The six highest ER-binding herbs that are commonly consumed were soy, licorice, red clover, thyme, tumeric, hops, and verbena. The six highest PR-binding herbs and spices commonly consumed were oregano, verbena, tumeric, thyme, red clover and damiana. Some of the herbs and spices found to contain high phytoestrogens and phytoprogestins were further tested for bioactivity based on their ability to regulate cell growth rate in ER (+) and ER (-) breast cancer cell lines and to induce or inhibit the synthesis of alkaline phosphatase, an end product of progesterone action, in PR (+) cells. In general, we found that ER-binding herbal extracts were agonists, much like estradiol, whereas PR-binding extracts, were neutral or antagonists. The bioavailability of phytoestrogens and phytoprogestins in vivo were studied by quantitating the ER-binding and PR-binding capacity of saliva following consumption of soy milk, exogenous progesterone, medroxyprogesterone acetate, or wild mexican yam products containing diosgenin. Soy milk caused a dramatic increase in saliva ER-binding components without a concomitant rise in estradiol. Consumption of PR-binding herbs increased the progestin activity of saliva, but there were marked differences in bioactivity. In summary, we have demonstrated that many of the commonly consumed foods, herbs, and spices contain phytoestrogens and phytoprogestins that act as agonists and antagonists in vivo.


 Diosgenin induces hypoxia-inducible factor-1 activation and angiogenesis through estrogen receptor-related phosphatidylinositol 3-kinase/Akt and p38 mitogen-activated protein kinase pathways in osteoblasts.:

 Diosgenin, extracted from the root of wild yam (Dioscorea villosa), has been reported to demonstrate an opportunity for medical application. Vascular endothelial growth factor-A (VEGF-A) plays an important role in bone-related angiogenesis, a critical process occurring during bone formation and fracture healing. In this study, we examine whether diosgenin is able to induce VEGF-A expression and to promote angiogenesis in osteoblasts. For murine MC3T3-E1 preosteoblast-like cells, VEGF-A mRNA and protein expression seemed to be significantly elevated in response to diosgenin in a concentration-dependent fashion. Conditioned media prepared from cells treated with diosgenin induced strong angiogenic activity in either in vitro or ex vivo angiogenesis assay. Furthermore, diosgenin treatment increased the stability and activity of HIF-1alpha protein. Inhibition of HIF-1alpha activity by transfection with DN-HIF-1alpha significantly diminished diosgenin-mediated VEGF-A up-regulation. The use of pharmacological inhibitors or genetic inhibition revealed that both the phosphatidylinositol 3-kinase (PI3K)/Akt and p38 signaling pathways were potentially required for diosgenin-induced HIF-1 activation and subsequent VEGF-A up-regulation. It is noteworthy that an estrogen receptor binding assay revealed that diosgenin has the strong ability to replace [(3)H]estradiol bound to estrogen receptor (IC(50), 10 nM). In addition, the specific estrogen receptor antagonists ICI 182,780 (faslodex) and tamoxifen were noted to be able to strongly inhibit diosgenin-induced, src kinase-dependent Akt and p38 MAPK activation. Taken together, such results provide evidence that diosgenin up-regulates VEGF-A and promotes angiogenesis in preosteoblast-like cells by a hypoxia-inducible factor-1alpha-dependent mechanism involving the activation of src kinase, p38 MAPK, and Akt signaling pathways via estrogen receptor.

 Phytoestrogens: a viable option?:

 Estrogen replacement therapy is one of the most commonly prescribed medicines in the United States by traditional medical professionals. Over the past decade, the market for complementary/ alternative therapies for hormone replacement has dramatically increased. Women are seeking more "natural" alternatives to treat menopausal symptoms. Well-designed randomized clinical trials are often lacking, as is the information on efficacy and safety. This article will review several popular herbal therapies for menopausal symptoms including phytoestrogens, black cohosh (Cimicifuga racemosa), dong quai (Angelica sinensis), chast tree (Vitex agnus-castus), and wild Mexican yam. Their use, mechanism of action, and adverse effects are outlined.


 "Bust enhancing" herbal products:

 "Bust enhancing" herbal products are widely advertised. No clinical trials have been published. These products contain a variety of ingredients, including grains, hops, saw palmetto, dong quai, chaste-tree berry, wild yam, kava, fennel, black cohosh, and fenugreek. Several of these herbs are hormonally active; for example, hops contain 8-prenylnaringenin, a phytoestrogen that is more potent than other dietary phytoestrogens. Many bust-enhancing dietary supplements contain substrates for Fusarium, a fungus that produces zearalenone, a potent estrogen that has been associated with breast enlargement in humans and other species. The use of bust-enhancing products should be discouraged because of lack of evidence for efficacy and long-term safety concerns.

 Hot flashes revisited: pharmacological and herbal options for hot flashes management.:

 Background: Hot flashes are the most frequent symptoms of menopause and the most common reason for climacteric women seeking medical advice. Estrogen therapy is by far the most effective therapy. However, fears of side-effect of estrogen therapy urged many patients to seek alternative modalities for symptomatic relief.

 Methods: The MEDLINE database for the years 1975-2004 was searched for clinical placebo-controlled trials for the treatment of hot flashes with alternative therapy. Articles reporting the use of progesterone, alpha adrenergic agonists, anti-depressants, anti-convulsants, soy products, black cohosh (BC), red clover, dong quai, ginseng root, evening primrose oil, vitamin E, and wild yam were included.

 Results and Conclusions: A critical review of the literature shows that progesterone may have an independent effect on relieving hot flashes. New nonhormonal agents such as selective serotonin-uptake-inhibitor anti-depressants and a new anti-convulsant gabapentin yielded promising results on small well-conducted studies. Isoflavone's effect on hot flashes is variable and inconsistent, and only modest and delayed improvement of symptoms could be expected by BC and vitamin E. There are insufficient data on the other herbal alternative therapies at this time. Well-designed large studies are needed to further explore new modalities of treatment.

 Diosgenin:a growth stimulator of mammary gland of ovariectomized mouse.:

 Estrogenic action of diosgenin on the mammary epithelium of ovariectomized (OVX) mouse has been reported. Diosgenin when administered (sc) at the dose levels of 20 and 40 mg/kg body weight for a period of 15 days stimulated the growth of mammary epithelium. This was indicated by the increase in DNA content, increase in number of ducts and appearance of terminal endbuds. There was a significant increase in the mammary development scores in the presence of diosgenin. Concomitant treatment of estrogen and diosgenin showed augmentation of estrogenic effect of diosgenin especially at the higher dose level (40 mg/kg body wt). Diosgenin showed a lack of progesterogenic action as was apparent from the absence of alveolar development even in the presence of exogenous estrogen.


 Effect of diosgenin on lipid metabolism in rats.:

 The purpose of this study was to determine whether diosgenin suppresses cholesterol absorption in rats, and to examine relevant changes in cholesterol and bile acid metabolism. Diosgenin fed with the diet for 1 week inhibited cholesterol absorption as determined by the serum isotope ratio technique, as well as by measuring in the feces the amount of unabsorbed radioactivity from orally administered [3H]cholesterol. In addition, diosgenin suppressed the serum and liver uptake of radioactivity from co-administered [3H]cholesterol as well as the accumulation of liver cholesterol in the cholesterol-fed rat; diosgenin was substantially more active than cholestyramine or beta-sitosterol. In vitro, diosgenin had no effect on the activity of rat pancreatic esterase. Diosgenin decreased the elevated cholesterol in serum LDL and elevated cholesterol in the HDL fraction of cholesterol-fed rats; diosgenin had no effect on serum cholesterol in normocholesterolemic rats. In contrast to cholestyramine, diosgenin markedly increased neutral sterol excretion without altering bile acid excretion; in vitro, diosgenin had no effect on bile acid binding. Diosgenin treatment increased hepatic and intestinal cholesterol synthesis as well as the activity of hepatic HMG CoA reductase. This was accompanied by increased biliary concentration of cholesterol, but not of bile acids. Diosgenin had no effect on cholesterol synthesis when added to normal rat liver homogenates. It was concluded that diosgenin interferes with the absorption of cholesterol of both exogenous and endogenous origin; such interference is accompanied by derepressed, i.e., increased, rates of hepatic and intestinal cholesterol synthesis. The increased unabsorbed cholesterol together with enhanced secretion of cholesterol into bile resulted in increased excretion of neutral sterols without affecting the biliary and fecal excretion of bile acids.

 Determination of diosgenin in Dioscorea:

 A method for the separation and determination of diosgenin in Dioscorea by reversed-phase high performance liquid chromatography was developed. The Rhizoma Dioscorea powder samples were extracted with methanol in a Soxhlet extractor. After extraction the solvent was evaporated and the extract was hydrolysed with 2 mol/L hydrochloric acid for 2 h in a boiling water bath. Then the diosgenin was extracted with petroleum ether (b.p. 60-90 degrees C). The operating conditions were Symmetry C8 column (5 microns, 3.9 mm x 150 mm) at 30 degrees C, mobile phase of V(acetonitrile):V(water) = 75:25 and UV detector at 203 nm. The linearity of the calibration curve was good in the range of 2.1-10.5 micrograms for diosgenin(r = 0.9994). The average recovery and RSD of diosgenin were 99.1% and 1.7% (n = 5) respectively. The method is accurate and reproducible and has been applied to the analysis of Rhizoma Dioscorea from different sources.

Reference:

• Wild Yam.Dioscorea villosa and Phytochemicals.

This article written and edited via herbalist of MDidea Extracts Professional. They run a range of online descriptions about this herb,including general information related and summarized updating discoveries from findings of professional scientisits this field related.Describe style aimed to form a useful detecting literature space where the intertwined threshold and related questions raise out and visualize themselves.

♣ last edit date:08th,Oct.2010.